Crybaby sweep range mod
Note: I have updated the wah since this page was posted. See the new page for details.
The Dunlop Crybaby uses a very simple and easy to modify circuit. Many folks have come up with mods for it over
the years, and one of the best resources I've found for information on the circuit and possible modifications
is Geofex. I will not attempt to repeat all
of the information contained in that link, as my purpose is to simply show what I did to my wah pedal.
Referring to the schematic above, the .01μF capacitor in the lower right hand corner is partially responsible for
setting the Q factor and center frequency of the filter circuit. Note that there are multiple versions of the Crybaby circuit. My wah uses a 3 transistor circuit that adds an input buffer to the schematic shown above, but the rest of the circuit is the same.
I added a switch and a second capacitor to my wah to
allow for a second sweep range. I doubled the value of the cap, which brings the center frequency down about an octave and widens
the Q a bit. The result is a deeper sound that works well for heavily distorted metal solos. I prefer the standard range for
clean work, and will often switch back and forth between the two sounds during a set.
The mod came out nicely out. No problems with the circuit, and the second sweep range adds some useful versatility.